A. Field of the Invention
This invention relates to microcapsules and to a method of use. In particular, this invention relates to chelating agents encapsulated in porous microscopic polymer shells, and to the use of these encapsulated chelating agents in removing metal ions from aqueous solutions.
B. Description of the Prior Art
Chelating agents are well known for their usefulness in both theoretical and applied chemistry and allied fields. Common uses include both qualitative and quantitative analyses as well as the softening of water, catalysis, and clarification of solutions. Chelating agents are particularly useful for the treatment of aqueous effluents to remove metallic impurities.
Chelating agents are traditionally used in either liquid ion exchange systems or in packed columns. In the former, an organic solution containing the chelating agent is placed in intimate contact with the aqueous solution and the removal of metallic ions is achieved when the two phases are separated. Unfortunately, it is often difficult to achieve a clean separation of the phases, and some loss of organic solvent invariably results. In the latter, the aqueous solution is passed through a column or "bed" of solid chelating resin, which is often mixed with a solid inert carrier. Such a process is often diffusion limited and requires large size equipment and a long residence time.
The object of the present invention is to provide an efficient system for metal ion removal which is free of these problems.